A detonation is a supersonic combustion wave associated with a shock wave propagating through a reactive mixture. The self-sustained detonation wave has a particular pressure and propagation velocity described as the Chapman-Jouget detonation. The Chapman-Jouget detonation shows a similar thermodynamic behavior to a constant volume combustion process which provides higher thermodynamic performance than constant pressure combustion. A pulsed detonation combustor (PDC) is a device which creates the self-sustained detonation waves in a cyclic fashion in order to convert their thermal energy to kinetic energy. Potential applications include engines in subsonic and supersonic flight, vehicles, and industrial power generators.
One of the technical challenges in pulsed detonation combustor is a valving scheme. Because of the unsteady nature of the wave, the combustor needs to provide combustible mixture in a cyclic fashion. FIG. 1 shows a schematic chronology of a cyclic ideal operation for a valved pulsed detonation combustor. Once the fill valve is closed, after the combustion mixture filling process, ignition is provided by a spark plug and deflagration to detonation transition process is initiated by a flame accelerator. After a short period of time, the purge valve starts to open to exhaust combustion products and to prepare the tube for the next filling process. A valved structure is able to realize a cyclic unsteady detonation initiation but it requires an additional mechanical complexity and poses mechanical/thermal fatigue issues for its long service.